The present invention relates to an adjustable bed base according to the preamble of the first claim.
With the bed base can be meant a slatted base or any other base of a bed.
An adjustable bed base is for example known from U.S. Pat. No. 5,537,701. The bed base described in U.S. Pat. No. 5,537,701 comprises a leg part for supporting the lower part of the body of a person lying on the bed base and a back part for supporting the upper part of this person's body. By means of an adjusting mechanism, the back part is adjustable with respect to the leg part between a lying position and an upright position, in which the back part encloses an obtuse angle with the leg part. The adjusting mechanism is constructed such that, upon moving the back part between the lying position and the upright position, the back part pivots with respect to the leg part and is also moved in longitudinal and height directions of the bed base. As a result, a displacement of the head end of a mattress lying on the bed base with respect to the back part and a displacement of the foot end of the mattress with respect to the leg part are prevented.
The bed base described in U.S. Pat. No. 5,537,701 however has the disadvantage that the adjusting mechanism for moving the back part between the lying position and the upright position comprises a complicated construction. This complicated construction is the result of the fact that the adjusting mechanism comprises, on the one hand, parts for accomplishing the pivoting movement of the back part and, on the other hand, parts for accomplishing the displacement of the back part along the longitudinal and height directions of the bed base. This leads to an adjusting mechanism, in which various parts move with respect to each other during the movement of the back part.
Further, a dentist chair is known from DE-A-39 01 379 with a leg part and a back part which are movable with respect to each other. To this end, the dentist chair comprises an adjusting mechanism which enables a rotation of the back part with respect to the leg part about a virtual pivoting axis, which is located in the pelvis of the person being seated in the chair. By this rotation about the virtual pivoting axis is achieved that a displacement of the person with respect to the chair can be prevented.